In fabricating disk drives, such as energy assisted magnetic recording (EAMR) disk drives, it may be necessary to bond substrates. For example, in conventional EAMR disk drives, a laser provides energy used to heat the media for magnetic recording. The laser typically takes the form of a laser diode. The laser diode may be desired to be bonded with the slider.
FIG. 1 depicts a conventional method 10 for bonding two substrates, such as a conventional laser diode (or substrate on which the laser diode resides) and a slider. FIGS. 2-3 depict a conventional EAMR head 50 during fabrication using the conventional method 10. Thus, two conventional substrates, a slider 60 and a laser diode 70 are shown. Each conventional substrate 60 and 70 includes conventional alignment marks 62 and 72, respectively. Each conventional substrate 60 and 70 also includes conventional solder pads 64 and 74, respectively. The conventional substrates 60 and 70 are aligned, via step 12. Typically this is accomplished by aligning the alignment marks 62 on one substrate 60 with the alignment marks 72 on the other substrate 72. FIG. 2 depicts the conventional substrates 60 and 70 after step 12. Thus, the alignment marks 62 and 72 and solder pads 64 and 74 are aligned.
Once alignment has been achieved, the substrates 60 and 70 are heated to reflow the solder 64 and 74. FIG. 3 depicts the conventional substrates 60 and 70 after step 14 is performed. Mechanical and electrical connection is made between the substrates 60 and 70 by pads 64′/74′, which have been reflowed together.
Although the conventional method 10 may function, the alignment achieved after the reflow step 14 may be limited. For example, after the method 10 is completed, the post-bonding alignment accuracy may be on the order of greater than one micron. For example, as can be seen by comparing FIGS. 2 and 3, the substrates 60 and 70 have moved with respect to each other after the reflow. In applications, such as EAMR heads 50, greater alignment accuracy is desired.
Accordingly, what is needed are improved methods and systems for bonding substrates, for example in bonding substrates used in EAMR disk drives.